Refrigeration systems are currently commonplace in commercial and residential buildings, and a variety of vehicles including, for example, automobiles, aircrafts, watercrafts, and trains. Over time, the refrigerant included in refrigeration systems its depleted and/or contaminated. As such, in order to maintain the overall efficiency and efficacy of a refrigeration system, the refrigerant included therein may be periodically replaced or recharged.
Refrigerant recovery units or carts are used in connection with the service and maintenance of refrigeration systems, such as air conditioning (A/C) systems. The refrigerant recovery unit connects to the A/C system to recover refrigerant out of the system and separate out oil and contaminants from the refrigerant in order to recharge or replace refrigerant into the A/C system.
The ability to obtain accurate weight measurements to get an accurate assessment of how much refrigerant is transferred to the A/C system is important to provide proper servicing. Inaccurate weight measurements result in inaccurate assessments of how much refrigerant actually was transferred to the A/C system during the charge, which can result in undercharging or overcharging the A/C system causing it to underperform. Consequently, in the automotive field, for example, the Society of Automotive Engineering (SAE) requires that refrigerant charging equipment have a charging accuracy of at least +/−15 grams in order to meet certification standards.
Refrigerant charging often needs to be conducted over a wide range of ambient and system conditions. Fluctuating conditions make the measuring and compensating for refrigerant charging changes difficult with existing charging equipment. For example, exposure of portions of the service hoses to a wide range of temperature ranges can cause undercharging as refrigerant tends to condense and remain in the cooler sections of refrigerant flow paths. Previously and currently used methods to equalize and clear flow paths are not optimal and sometimes forbidden by manufacturers' specified charging requirements.
As a consequence of the foregoing, a need exists for a refrigerant recovery unit and methods associated therewith that can improve the charge accuracy of refrigerant charging equipment such as refrigerant recovery units.